Since the radio button can only have one value attributed to it (technically), I would do away with $radio_1, $radio_2, and $radio_3, and just have a variable which states which radio button was selected.

Code

for (1, 2, 3) { $rnum = $_, last if $radio eq "Choice $_"; }

If the values are more complex than "Choice 1", "Choice 2", etc., then put them in an array, and go over it by index (yes, by index!):